Abstract
The superposed epoch analysis (SEA) method is a traditional extraction method for the solar quiet daily variation (Sq) and obtains the monthly Sq by the averages of the data on the international five quietest days (five Q-days) in one month. This study tried to optimize this method through two technical measures, increasing the number of calculation days and moving the calculation period day by day. To test the effectiveness of the new method, the observatory data were decomposed into Sq components and non-Sq components by the characteristic of Sq varying with local time (LT). The observatory data were reconstructed by correcting the Sq components for time differences. Then, the two Sq extraction methods were evaluated based on the correlation coefficient and mean square error (MSE) of the difference between the reconstructed data and the reference observatory data. Comparison with the traditional method showed that the correlation coefficients for the three factors H, D, and Z were improved by 0.0142, 0.0017, and 0.0235, and MSEs were improved by 0.24 nT, 0.03´, and 0.17 nT, respectively, indicating that the Sq results are more reasonable.
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This work was Supported by Hebei Province Spark Program of Earthquake Sciences (DZ20190422046). We thank the China Earthquake Administration and Hebei Earthquake Agency for their support.
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Shupeng Su, Zhang, H. & Zhao, H. Moving Superposition Method for Sq Extraction and the Effectiveness Evaluation. Geomagn. Aeron. 62, 657–662 (2022). https://doi.org/10.1134/S0016793222050139
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DOI: https://doi.org/10.1134/S0016793222050139